1. Technical Field
This invention relates generally to ink jet printers. More specifically, this invention relates to ink jet printing of color images on transparent or translucent substrates.
2. Description of the Related Art
Backlit printing is a particular type of printing process for printing or applying images onto a substrate that is transparent or translucent with the intention of such images being lit from behind. An example of a backlit print is a large poster applied to the side of a bus stop sitting enclosure, where the natural light from the sun has the effect of lighting up the poster from behind for any individual passing by or sitting at the bus stop. Another example of a backlit print is a large, lit-up display of a vendor's perfume advertisement at a perfume section of a department store with the intention of getting the customer's attention in a large and attractive way.
An example of a method and apparatus for backlit imaging can be found in U.S. Pat. No. 7,562,957, METHODS AND APPARATUS FOR BACKLIT AND DUAL-SIDED IMAGING, issued Jul. 21, 2009 (referred to herein as '957) to inventor, M. D. Mills, and to M. Syverson, which is incorporated herein in its entirety by this reference thereto. It should be appreciated that '957 provides a detailed description of the technical background of backlit printing, which need not be reproduced herein, but rather, is incorporated herein by reference.
As '957 discloses, an example process for backlit imaging may be performed by printing a first image on the reverse side of a transparent substrate and subsequently printing over such first image with one or two layers of white ink. The white layer(s) serves as a backdrop such that the colors of the image appear properly when viewed for example from the front side of the transparent substrate. Then, a second image, which may be essentially the same image as the first image, is printed over the white layer(s). See, for example, FIG. 3C and FIG. 3D. Thus, in the end, an observer may view the first image in ambient light from the non-printed side of the transparent substrate and may view the second image in ambient light from the printed side of the transparent substrate.
Further, the process as taught in '957 has been found to be very slow and may reduce the speed of the printer by at least 70% and as much as 80%.